Transcript DCOM
DCOM (Overview) byJeevan Varma Anga DCOM Overview What is DCOM? Why DCOM? Architecture What is DCOM? Distributed Component Object Model “COM with a longer wire” Microsoft Press Release 9/96 “Application-level protocol for object-oriented remote procedure calls.” IETF Internet Draft 5/96 “Object RPC” The Distributed Component Object Model (DCOM) is a protocol that enables software components to communicate directly over a network in a reliable, secure, and efficient manner. Previously called "Network OLE," DCOM is designed for use across multiple network transports, including Internet protocols such as HTTP. Why DCOM? Components And Reuse Location Independency Language Neutrality Connection Management Location independence Why DCOM? Scalability • • • Symmetric Multiprocessing (SMP) Flexible Deployment Robust versioning Performance Bandwidth and Latency Security • • • Security by configuration Programatic control Internet control Why DCOM? Load Balancing • • Static Load Balancing Dynamic Load Balancing Fault Tolerance Ease of Deployment Protocol Neutrality Platform Neutrality Fault Tolerance COM/DCOM Architecture Client Server Client Application Server Implementation Proxy Stub Channel COM Clients - Proxies map object method invocations into calls to COM/DCOM objects COM Servers - In-Process - Local - Remote Overall DCOM Architecture In-Process Servers Local Servers Remote Servers Summary DCOM makes it easy to write a distributed application Provides rich, symmetric communication between components. Can be robustly expanded to meet new functional requirements. Takes advantage of existing custom and off-the-shelf components. Integrates teams proficient in any programming language and development tool. Uses network bandwidth carefully, while providing great response times for end-users. Is inherently secure. Provides a smooth migration path to sophisticated loadbalancing and fault-tolerance features. Can be efficiently deployed and administered. Can be used with any network protocol and integrated into any hardware platform. DCOM is the TCP/IP of objects. Want to know more? Specification – N. Brown, C. Kindel, “Distributed Component Object Model Protocol -- DCOM/1.0,” IETF Networking Group Internet-Draft, Microsoft Corporation, Jan, 1998 Programming – R. Grimes, “Professional DCOM Programming”.